Work is progressing on three projects related to the physiology and pharmacology of the renin-angiotensin system. 1. The effect of Ca ion and other cations on angiotensin-induced contractions of uterine and vascular smooth muscle is being studied. In addition, drugs known to modify Ca ion metabolism are also being tested for their ability to block angiotensin effects on smooth muscle. 2. The contribution of the sympathetic nervous system to the hypertensive response elicited by angiotensin is also under study. Evidence suggests a direct action of angiotensin on the postganglionic sympathetic fiber. Further studies are under way to determine if this is an effect at the level of the cell body or at the nerve terminals. 3. Studies are also under way to determine the feasibility of incorporating lipophilic groups into synthetic peptides.